Heads or Pistons
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Let me tell you about some unknown facts about the purchase of aluminum heads.
The rocker stud "pad" on most aluminum heads is about 0.100 higher than stock. What's the big deal? Your stock pushrods will no longer furnish the proper geometry.
No $19.95 rods will work here. Longer pushrods will run around $80 - $100 a set. Must be harden for the guide plates and one piece are better rods. Plus you will need a length checker tool to confirm before purchase of rods.
You will need ARP head bolts at $120. Stock bolts will gouge the soft head. You need a built in washer under the bolt head, which ARPs have.
You will need expensive head gaskets. Again, $19.95 units will not work here. You have two different metals with different expansion rates that must be sealed.
Figure around $50 EACH !
But the rewards of aluminum heads is priceless.
The rocker stud "pad" on most aluminum heads is about 0.100 higher than stock. What's the big deal? Your stock pushrods will no longer furnish the proper geometry.
No $19.95 rods will work here. Longer pushrods will run around $80 - $100 a set. Must be harden for the guide plates and one piece are better rods. Plus you will need a length checker tool to confirm before purchase of rods.
You will need ARP head bolts at $120. Stock bolts will gouge the soft head. You need a built in washer under the bolt head, which ARPs have.
You will need expensive head gaskets. Again, $19.95 units will not work here. You have two different metals with different expansion rates that must be sealed.
Figure around $50 EACH !
But the rewards of aluminum heads is priceless.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
You will need expensive head gaskets. Again, $19.95 units will not work here. You have two different metals with different expansion rates that must be sealed.
Figure around $50 EACH !
Figure around $50 EACH !
https://www.summitracing.com/parts/FEL-7733SH1
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Why? what is wrong with the felpro .015" shim head gasket?
https://www.summitracing.com/parts/FEL-7733SH1
https://www.summitracing.com/parts/FEL-7733SH1
They are awesome for cast iron heads......only application I have used either on.....
Jebby
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
These are not a good idea on Aluminum heads......Fel Pro makes a .018 thick one with rubber coating.....good for stock block but if the engine is machined zero deck then you shouldn't use it.
They are awesome for cast iron heads......only application I have used either on.....
Jebby
They are awesome for cast iron heads......only application I have used either on.....
Jebby
Of course if it's zero decked you need a thicker one aluminum, or cast iron.
For stock decks it's the perfect thickness.
I've had my felpro shim head gasket with my AFR heads and before Dart SHP's stock deck height for over 12,000 miles and 8 years now, no issues what so ever. just used a little K&W copper coat sealer on both sides to insure the seal.
Last edited by REELAV8R; Apr 6, 2021 at 12:23 PM.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Again, Why?
Of course if it's zero decked you need a thicker one aluminum, or cast iron.
For stock decks it's the perfect thickness.
I've had my felpro shim head gasket with my AFR heads and before Dart SHP's stock deck height for over 12,000 miles and 8 years now, no issues what so ever.
Of course if it's zero decked you need a thicker one aluminum, or cast iron.
For stock decks it's the perfect thickness.
I've had my felpro shim head gasket with my AFR heads and before Dart SHP's stock deck height for over 12,000 miles and 8 years now, no issues what so ever.
That is cool that you had good luck with them (the .015) but I would not use it myself and knowingly install it.....that is what the 1094 Fel pro is for but I see now they changed it.....eliminated the rubber coating and have some kind of clearcoat on it now......
Basically there is no "crush" like a composite to fill imperfections and/or warping......but on a freshly machined unit, it should be fine......but all of my freshly machined **** is all zero deck so no bueno.
Jebby
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
Imperfections is what K&W copper coat sealer is for.
as far as differential expansion rates causing failed head gaskets goes, I have heard that as long as I can remember, heard it maybe first time in the late 70’s to early 80’s.
of course aluminum and cast iron do expand differently, but that is not cause for a failed head gasket. It might contribute in extreme cases, super high performance etc, not in street built stuff we deal with.
i’m running 10.6:1 6300 RPM, blowing 200 psi on a compression check. If it was gonna fail due to differential expansion rates it would have already happened.
All this was discussed before I built my engine and I could find no evidence to support the contention that you can’t/ shouldn’t run a steel shim gasket with cast iron block and aluminum head. So I did. Still going strong so far.
as far as differential expansion rates causing failed head gaskets goes, I have heard that as long as I can remember, heard it maybe first time in the late 70’s to early 80’s.
of course aluminum and cast iron do expand differently, but that is not cause for a failed head gasket. It might contribute in extreme cases, super high performance etc, not in street built stuff we deal with.
i’m running 10.6:1 6300 RPM, blowing 200 psi on a compression check. If it was gonna fail due to differential expansion rates it would have already happened.
All this was discussed before I built my engine and I could find no evidence to support the contention that you can’t/ shouldn’t run a steel shim gasket with cast iron block and aluminum head. So I did. Still going strong so far.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Imperfections is what K&W copper coat sealer is for.
as far as differential expansion rates causing failed head gaskets goes, I have heard that as long as I can remember, heard it maybe first time in the late 70’s to early 80’s.
of course aluminum and cast iron do expand differently, but that is not cause for a failed head gasket. It might contribute in extreme cases, super high performance etc, not in street built stuff we deal with.
i’m running 10.6:1 6300 RPM, blowing 200 psi on a compression check. If it was gonna fail due to differential expansion rates it would have already happened.
All this was discussed before I built my engine and I could find no evidence to support the contention that you can’t/ shouldn’t run a steel shim gasket with cast iron block and aluminum head. So I did. Still going strong so far.
as far as differential expansion rates causing failed head gaskets goes, I have heard that as long as I can remember, heard it maybe first time in the late 70’s to early 80’s.
of course aluminum and cast iron do expand differently, but that is not cause for a failed head gasket. It might contribute in extreme cases, super high performance etc, not in street built stuff we deal with.
i’m running 10.6:1 6300 RPM, blowing 200 psi on a compression check. If it was gonna fail due to differential expansion rates it would have already happened.
All this was discussed before I built my engine and I could find no evidence to support the contention that you can’t/ shouldn’t run a steel shim gasket with cast iron block and aluminum head. So I did. Still going strong so far.
Jebby
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
To each his own. And if you’re making a living at it why take the risk? I get that.
But headsup contention is that you can’t. Yet You can and I did. And I know many others here have too. Too many “ rules of thumb” get passed on to the uninitiated, in every hobby. If some asks why, shouldn’t there be an answer?
I was told to never use KB hyper pistons because the top ring land would rip off. Wrong again. They work fine, great even, just have to set the top ring gap properly.
“don’t use a 108 LSA cam in a 350” I did the research and decided to do just that. It works fantastic!
I know some may be trying to head off expensive mistakes of others and that’s admirable.
However if we say “don’t do this” for some reason and the question “ why” is posed then it deserves a reasonable answer backed by facts and not hobby lore.
But headsup contention is that you can’t. Yet You can and I did. And I know many others here have too. Too many “ rules of thumb” get passed on to the uninitiated, in every hobby. If some asks why, shouldn’t there be an answer?
I was told to never use KB hyper pistons because the top ring land would rip off. Wrong again. They work fine, great even, just have to set the top ring gap properly.
“don’t use a 108 LSA cam in a 350” I did the research and decided to do just that. It works fantastic!
I know some may be trying to head off expensive mistakes of others and that’s admirable.
However if we say “don’t do this” for some reason and the question “ why” is posed then it deserves a reasonable answer backed by facts and not hobby lore.
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Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
To each his own. And if you’re making a living at it why take the risk? I get that.
But headsup contention is that you can’t. Yet You can and I did. And I know many others here have too. Too many “ rules of thumb” get passed on to the uninitiated, in every hobby. If some asks why, shouldn’t there be an answer?
I was told to never use KB hyper pistons because the top ring land would rip off. Wrong again. They work fine, great even, just have to set the top ring gap properly.
“don’t use a 108 LSA cam in a 350” I did the research and decided to do just that. It works fantastic!
I know some may be trying to head off expensive mistakes of others and that’s admirable.
However if we say “don’t do this” for some reason and the question “ why” is posed then it deserves a reasonable answer backed by facts and not hobby lore.
But headsup contention is that you can’t. Yet You can and I did. And I know many others here have too. Too many “ rules of thumb” get passed on to the uninitiated, in every hobby. If some asks why, shouldn’t there be an answer?
I was told to never use KB hyper pistons because the top ring land would rip off. Wrong again. They work fine, great even, just have to set the top ring gap properly.
“don’t use a 108 LSA cam in a 350” I did the research and decided to do just that. It works fantastic!
I know some may be trying to head off expensive mistakes of others and that’s admirable.
However if we say “don’t do this” for some reason and the question “ why” is posed then it deserves a reasonable answer backed by facts and not hobby lore.
I have used the steel shim many times though....but always on an aluminum head.....all of the top builders will tell you the same thing....a top builder taught me, and that is how I roll.
I have KB pistons and a 108 LSA cam in my 406 BTW LOL!!!
Jebby
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
I don’t do this for a living....I used to, but it made me hate people so I stopped 12 years ago. It is strictly a hobby. Having said that.....a fresh build has no place for an .015 gasket in my world regardless of head....and on a GM machined engine, I don’t feel good using a steel shim on a block that has tooling marks on it with an aluminum head. No one else I know does either.....if you did, cool. But for the average bonehead in their garage, I won’t recommend it.
I have used the steel shim many times though....but always on an aluminum head.....all of the top builders will tell you the same thing....a top builder taught me, and that is how I roll.
I have KB pistons and a 108 LSA cam in my 406 BTW LOL!!!
Jebby
I have used the steel shim many times though....but always on an aluminum head.....all of the top builders will tell you the same thing....a top builder taught me, and that is how I roll.
I have KB pistons and a 108 LSA cam in my 406 BTW LOL!!!
Jebby
"The average bonehead" LOL that's funny!
I had no teacher and therefore no predisposition or instruction to do something a certain way, Never took a shop class in school, nada, Just figured it out as I went along. Started with small motors and worked my way up, and used Hanes manuals (at the time is was the best source of info I could afford) and any other books I could get my hands on from experts that were motivated enough to put down their expertise in writing. The internet has helped greatly. Back in the 80's and 90's it was trial by error mostly.
Last edited by REELAV8R; Apr 6, 2021 at 06:00 PM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Reelav8R,
I never said you can't use a shim. I stated that with unlike metals, plan on using a quality head gasket and not some flimsy piece of ****.
To me, a shim is just that. Something to shim-up a given gap. Perhaps to place a shim under a head gasket. Or over a head gasket to get the thickness you desire. IDK. Never used them. Don't know about them. But you should spend a few bucks on quality gaskets regardless.
Just because somebody does a procedure on this forum and "got away with it" for years, does not mean its right, nor does it mean its wrong.
A classic example are those choose not to run Zinc in a flat tappet cam engine. Is it wrong? Is it right?
To me, some people are just running on borrowed time.
I never said you can't use a shim. I stated that with unlike metals, plan on using a quality head gasket and not some flimsy piece of ****.
To me, a shim is just that. Something to shim-up a given gap. Perhaps to place a shim under a head gasket. Or over a head gasket to get the thickness you desire. IDK. Never used them. Don't know about them. But you should spend a few bucks on quality gaskets regardless.
Just because somebody does a procedure on this forum and "got away with it" for years, does not mean its right, nor does it mean its wrong.
A classic example are those choose not to run Zinc in a flat tappet cam engine. Is it wrong? Is it right?
To me, some people are just running on borrowed time.
Last edited by HeadsU.P.; Apr 6, 2021 at 07:48 PM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Why? what is wrong with the felpro .015" shim head gasket?
https://www.summitracing.com/parts/FEL-7733SH1
https://www.summitracing.com/parts/FEL-7733SH1
So, when adding aluminum heads you are no longer stock, correct?
And, the $11 price tag should send a red flag so far in the air that China can see it. Eleven dollars? Really?
Race Director
Joined: Mar 2018
Posts: 10,713
Likes: 2,168
From: Golden Colorado
So now you guys got me thinking about an engine I’m working on. SBC iron block squared but not zero decked. AFR aluminum heads. I was going to use Fel pro shim but when they came they did not have the rubber coating on them. I called and they said they were discontinued. What is the thinnest composite head gasket available?
Thx in advance.
Thx in advance.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
I think what this topic boils down to is the false assumption that too thick a head gasket will cause a loss of incredible horse power. But at the cost of what? A breached shim?
In my non-pro opinion, I would rather give up a smidge of compression ratio in favor of a seal that lasts for decades. Coolant in the cylinder is not purdy.
What does Summit have for thinner gaskets? After punching in the yr-make-model-bore Gen 1 ?????
In my non-pro opinion, I would rather give up a smidge of compression ratio in favor of a seal that lasts for decades. Coolant in the cylinder is not purdy.
What does Summit have for thinner gaskets? After punching in the yr-make-model-bore Gen 1 ?????
Race Director
Joined: Mar 2018
Posts: 10,713
Likes: 2,168
From: Golden Colorado
Since I’m at elevation over 5000 thin air every bit of compression is precious. I’m at 4.030 bore gen 1 sbc and most gasket thickness composite is .039 to .041. This is why I liked the Fel pro rubber at under .020. 
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
usually high quality goes with high cost, but after all it’s just a stamped piece of metal, how much should it cost?
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Jebby
Drifting
Joined: Aug 2004
Posts: 1,883
Likes: 124
From: Lubbock TX
I would recommend heads to you, but if you are only interested in Chinese junk, then you are really not looking for anything good. I know not everyone has money to spend, but the difference between junk and good quality is really not much money in the big scheme of things. The very best heads made are AFR, and they can be bought for $1769 at Summit. Then there is a long list of heads less than that that at least are good quality American made heads, includes Edelbrock, Dart, RHS, Profiler, etc. I am no expert, but I believe "you get what you pay for".
Best budget heads today are probably ProMaxx. Very high quality and bang for the buck puts this one at or near the top of this category.
Le Mans Master
Joined: May 2007
Posts: 5,028
Likes: 1,120
From: North tonawanda NY
Again, Why?
Of course if it's zero decked you need a thicker one aluminum, or cast iron.
For stock decks it's the perfect thickness.
I've had my felpro shim head gasket with my AFR heads and before Dart SHP's stock deck height for over 12,000 miles and 8 years now, no issues what so ever. just used a little K&W copper coat sealer on both sides to insure the seal.
Of course if it's zero decked you need a thicker one aluminum, or cast iron.
For stock decks it's the perfect thickness.
I've had my felpro shim head gasket with my AFR heads and before Dart SHP's stock deck height for over 12,000 miles and 8 years now, no issues what so ever. just used a little K&W copper coat sealer on both sides to insure the seal.
After recently snapping an afr balancer bolt and drilling through it like butter with a harbor freight bit I'm not as convinced its much better than grade 8 hardware.
Its funny you mention "hobby lore" as my new favorite tv show has been Engine masters and they have disclaimed many internet myths ive read repeated multiple times. I mentioned recently in the radiator sticky about the comparision I recently saw between different radiator fans they did on the dyno to prove by demonstration how much of a difference it really makes and the first response here was someone claiming BS.. Bias is a funny thing. I myself was thrilled to learn I could free up as much as almost 30hp at higher rpms by just going to electric fans.
By the same token I wasnt so happy to learn how much potential hp I lost due to the dent I put in one of my header collectors to clear the steering box.. but I dont discredit it as BS either..
Last edited by augiedoggy; Apr 7, 2021 at 07:13 AM.
Le Mans Master
Joined: May 2007
Posts: 5,028
Likes: 1,120
From: North tonawanda NY
There are a lot of engine builders and racers that would argue that AFR aren't the "very best head". They're very good but have not proven themselves to be clearly superior to some others. Not one of the major builders in the country uses AFR unless asked to, most use Brodix or Dart or even their own proprietary head. Not arguing that AFR makes some great heads, but there's no "very best head" made by anybody, new stuff is out every day.
Best budget heads today are probably ProMaxx. Very high quality and bang for the buck puts this one at or near the top of this category.
Best budget heads today are probably ProMaxx. Very high quality and bang for the buck puts this one at or near the top of this category.
Every time someone asked about heads here, budget or not, they are often discouraged into being told they need to spend top dollar regardless of the rest of their combo and actual goals regardless of all the choices in between. The Real AFR specific made heads are some of the best, and no doubt heads are the single most important item IF you plan on building a true performance engine to support them. Otherwise there are MANY options that will still offer plenty of gain over stock on a mild engine.
Last edited by augiedoggy; Apr 7, 2021 at 07:31 AM.